In the past, imaging diagnosis has been performed by inserting a probe having an imaging function into a blood vessel of a coronary artery of the heart or the like and a vessel of a bile duct or the like.
One type of imaging diagnostic apparatus is an intra vascular ultra sound (IVUS: Intra Vascular Ultra Sound) diagnostic apparatus. Generally, the intra vascular ultra sound diagnostic apparatus is constructed such that a probe equipped with an ultrasonic transducer is scanned radially in the blood vessel, a reflection wave (ultra sound echo) reflected by biological tissue in a coelom is received by the same ultrasonic transducer, and thereafter processes such as amplification, detection and the like are applied and a cross-section image of a blood vessel is visualized based on the strength of the generated ultra sound echo.
Another imaging diagnostic apparatus is an optical coherent tomography (OCT: Optical Coherence Tomography) diagnostic apparatus. An example of an optical coherent tomography diagnostic apparatus is disclosed in Japanese Unexamined Patent Publication No. 2007-268133. The optical coherent tomography diagnostic apparatus is an apparatus in which a probe equipped with an optical fiber which is mounted with a probe equipped with an optical lens and an optical mirror at the distal tip is inserted into a blood vessel, light is illuminated into the blood vessel while radially scanning the optical mirror arranged on the distal side of the optical fiber, and the cross-section image of the blood vessel is to be visualized based on the reflected light from the biological tissue. Further, there is proposed nowadays an imaging diagnostic apparatus which uses an optical frequency domain imaging (Optical Frequency Domain Imaging: OFDI) method which is referred to as a next generation OCT.
Japanese Unexamined Patent Publication No. 2004-275200 describes a catheter 1 in which the proximal side of a flexible tube 4 is held by a holding member H. The tube 4 in the vicinity of the holding member H includes a coil shaped reinforcement member 42 in the inside of the tube wall, and the proximal side of this coil shaped reinforcement member 42 is covered by a pipe-shaped reinforcement member 43. This pipe-shaped reinforcement member 43 is held on the holding member H.
Also, Japanese Unexamined Patent Publication No. 2003-61963 proposes an ultra sound catheter 1 provided with a built-in driving shaft 10 in a catheter sheath 2 which transmits a mechanical driving force from the hand side to the distal side of the catheter sheath 2 and with an ultra sound vibrator 13 connected to the distal side of the driving shaft 10. An X-ray opacity applying unit 12 is provided at least at a portion of the driving shaft 10. Paragraph [0021] of Japanese Unexamined Patent Publication No. 2003-61963 discloses that the catheter sheath 2 is formed, for example, by a multi-layer structure of resins such as polyimide, polyamide, polyester, polyethylene and polyurethane, and there is provided a reinforcement body of a metal-made knitted braid, a flat plate coil or the like between the resin layers on the proximal side from a position at which an intraluminal ultrasonic transducer can exist.
Also, Japanese Unexamined Patent Publication No. H09-070403, proposes an ultra sound catheter including an exterior shaft inserted into a coelom, a driving shaft inserted into the exterior shaft and transmitting a mechanical driving force from the proximal side to the distal side, and a housing provided with an ultrasonic transducer and fixed at the driving shaft so as to be positioned in the inside on the distal side of the exterior shaft and in which the driving shaft is an ultra sound catheter rotatable by an external driving source, wherein the exterior shaft includes a first elastic member of a coil shape at the distal portion, the housing includes a second elastic member extending to the distal side of the catheter at the distal portion, and the distal tip of the second elastic member is positioned in the first elastic member. Then, with respect to the main body portion of the exterior shaft, there is proposed a main body portion having a reinforcement layer positioned between the exterior and the interior layer and at the same time, the following matters are disclosed for the reinforcement layer.
At the distal portion of a tube which forms an intermediate layer (reinforcement layer) 102b (for example, elastic metal tube), there is provided a spiral shaped slit extending from the distal tip to the rear end side. Thus, the distal portion of the elastic metal tube forms a deformable portion which is flexible compared with other portions, so that with respect to the distal portion of the elastic metal tube, it is possible for the side wall thereof to be deformable toward the inside of the super-elastic metal tube. It is preferable for the slit to be formed to have widths gradually smaller from the distal tip toward the rear end side of the elastic metal tube, in other words, to have widths which become gradually larger toward the distal side. For this reason, the slit width at the distal tip of the elastic metal tube is formed to be maximum, and the more nearer the elastic metal tube is directed toward the distal tip, the more easily the deformation thereof occurs. It is preferable for the slit to be provided as many as around 2 to 8 pieces by being approximately equally spaced. It is preferable for the distal width of the slit (width of the maximum portion) to be around 0.05 mm to 0.5 mm. Also, it is preferable for the slit width to be approximately ⅙ to 3/2 of the outer diameter of the elastic metal tube and in particular, to be approximately ⅓ to 1/1 thereof. Also, with respect to the spiral shaped slit, it is also allowed for the pitch thereof to be short on the distal portion side of the slit and to be long on the proximal portion side of the slit. In a case in which the slit pitch changes, around 0.3 mm to 3.0 mm is preferable at the distal portion and around 5 mm to 10 mm is preferable at the proximal portion and in particular, at the middle portion between the distal portion and the proximal portion, it is preferable to have an intermediate pitch of the both sides or to have pitches gradually changing therebetween. Also, it is preferable for the slit 19 to have the changing pitches and the changing widths mentioned above.